One of the primary structural components of a bicycle is the bicycle crossbar. In typical bicycle construction, the crossbar is rigidly secured to and extends between a head tube of the bicycle and a seat tube of the bicycle. The head tube typically provides a structural base for the stem of the bicycle to which the handle bars are attached. The seat tube provides a base for a seat post which is generally telescopically received therewithin and to which is secured the saddle or seat of the bicycle.
In the construction of multiple speed bicycles, generally three cables extend from the front of the bicycle along the crossbar toward the rear of the bicycle. These cables typically include the rear brake cable, a first shifter cable which is interfaced to the front sprocket derailleur, and a second shifter cable which is interfaced to the rear sprocket derailleur. Typically, the three aforementioned cables are secured either along the top or the bottom of the crossbar via fasteners such as clips. In some prior art bicycles, these cables are inserted through the interior of the crossbar which is typically constructed from cylindrical, tubular stock. In those instances where the cables are attached to the outer surface of the crossbar, the cables are susceptible to damage or breakage and, particularly with mountain bikes, are exposed to substantial amounts of dirt. Additionally, the exposed cables present a safety hazard to the bicycle rider in that the rider's extremities may contact or become entangled in the cables when falling off the bicycle. In those instances where the cables are inserted through the crossbar, apertures must be formed in the head tube, seat tube and/or crossbar components of the bicycle to permit passage of the cables therethrough. As will be recognized, the inclusion of such apertures in the head, seat and/or crossbar tubes diminishes the structural integrity of the resultant bicycle frame.
Additionally, in constructing bicycle frames, it is generally desirable to permanently and rigidly affix the opposed ends of the crossbar to the head and seat tubes through the use of a conventional butt weld or a brazing technique to provide the frame with greater structural integrity. However, such prior art crossbars when formed with apertures or channels to facilitate the brake and sprocket cable transport cannot be affixed to the head and seat tubes through the use of a butt weld or brazing techniques since the crossbars are constructed from tubular stock of insufficient wall thickness to support the use of these attachment methods. The present invention overcomes these and other deficiencies associated with prior art bicycle frame crossbars.